Mechanical and tribological properties of SiC-GNPs composites prepared by oscillatory pressure sintering

Abstract

SiC-based ceramics, as structural parts and wear-resistant parts, are required to possess outstanding mechanical properties and wear resistant. Herein, to prepare SiC-based ceramics with desirable properties, the effects of graphene nanoplatlets (GNPs) content on the densification, microstructure, mechanical and tribological properties of SiC-GNPs composites by using an oscillatory pressure sintering (OPS) process were investigated. The addition of GNPs could inhibit the growth of SiC grains, and the resultant mechanisms such as crack bridging, deflection, and GNPs pull-out also promoted the strengthening and toughening of such composites. The flexural strength and fracture toughness of the SiC-1.0 wt% GNPs composites attained the maximum values of 515 MPa (∼27% increase) and 7.11 MPa·m1/2 (∼26% increase), respectively. In addition, the friction behavior of SiC-GNPs composites was analyzed by selecting GCr15 steel ball as friction side under drying friction conditions. Compared with pure SiC ceramics, the friction coefficient and wear rate of SiC-1.0 wt% GNPs ceramics were as low as 0.65 (reduced by ∼25%) and 5.17 × 10−7 mm3·N−1·m−1 (reduced by ∼41%), respectively. This phenomenon can mainly be attributed to the lubricating film formed by GNPs during sliding and excellent mechanical properties.